HPCC-9597 Combine multiple ds[1].<field> into a single row

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4594 from ghalliday/issue9597

HPCC-9597 Combine multiple ds[1].<field> into a single row

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>